"Lost boy" and author Brent Jeffs speaks about his new book about FLDS polygamy.

"Lost Boy" by Brent W. Jeffs, Broadway Books, 235 pages, $25

He looks like any other 20-something you'd pass on the street. Short, dark hair, striped button-down shirt, sunglasses, jeans. He comes from a large family, but that's not uncommon in Utah. That is, until you realize just how big his family is.

Brent Jeffs, grandson of polygamist Rulon Jeffs and nephew of Warren Jeffs, grew up in the Fundamentalist LDS Church and has a new book on his experience, titled "Lost Boy."

The book chronicles his childhood within the FLDS Church and the struggles he faced after leaving it.

Spurred to action by the deaths of two of his brothers, who fell victim to drug and alcohol abuse after leaving the FLDS Church, Jeffs said he committed his life to reaching out to others who have defected from — and been abused by — the FLDS Church.

"When my brother told me what happened to him and then he passed away, that's when it was like a volcano," Jeffs said. "I just said ... I'm going to go put 110 percent into this thing and go all the way with this, and I am blown away that I am here now in this point in my life, that it has gone this far."

Because his history is graphic with accounts of sexual abuse, Jeffs said his family initially reacted with hesitation and fear, even though his parents and all but two siblings have left the FLDS Church.

"In the beginning, they were scared, because they kind of didn't understand where I was coming from," he said. "They thought I was retaliating ... but as soon as they saw where I was going and the direction of the book, they were very supportive."

One major focus of the book is Jeffs' decision to leave the FLDS Church and the struggles he faced in the outside world. Though he had the advantage of two parents who willingly helped and supported him, Jeffs said he felt socially and culturally out of place.

"All of the sudden, you are in the outside world, and you have to force yourself to find a job, talk to people, talk to girls, all that stuff, and I had no clue," he said. "I was scared. I didn't know what to do. I would just immediately get nervous and close down and not be able to talk to anybody, so for me, that was probably the hardest thing."

Jeffs said he also came to realize that all the people in the outside world weren't "horrible, mean, ugly people," as he had been taught. He said many people have helped him in accomplishing many things, such as filing a lawsuit against Warren Jeffs that ultimately led to the FLDS leader's imprisonment.

"That was so relieving, so gratifying," Brent Jeffs said. "It felt so good to finally see him go to court and see him the way he was. He knows ... good and well what he did and how many people's lives he's ruined, and so it was amazing for me."

Though Brent Jeffs said it was difficult to piece together the chronology and revisit painful memories, writing the book has ultimately been a cathartic experience.

"Through this book, I finally get to let go of all that pain and anger and all that stuff I held in all those years," he said. "That part of me is healed. That part of me is OK."